Thursday, March 01, 2007

No Wonder

I thought we were having an awfully long gray spell. According to wunderground.com, the last day we had completely free of rain was February 5. We only had a trace on Feb. 6 and 17, but we've had measurable accumulations every other day since the 5th, with another week of rain forecasted!

I think rain and 42 degrees F (502 Kelvin, if I remember correctly -- that sounds warmer!) can be colder than snow and 30 degrees F. Oh well. Despite their geriatric status, the troops wish to go out for a walk. Who am I to deny them? Off we go!

Update: we're back, and I checked Weather Underground again. Despite having only 3 rain-free days in February, we had almost an inch less rain than an average February! We only had 3.97 inches instead of 4.86.

I started thinking about our rainfall on the walk (since it was raining at the time). We have about the same yearly rainfall as most of the places I've lived in the east and midwest. Like those places, we have about 30-36 inches of rain a year. Let's call it 36"/year or averaging 3 inches per month. That doesn't sound too bad: an average of about 0.1 inches per day, so you expect a lot of days of sun and a few of rain.

West of the Cascades, though, we have some very dry months. Typically we have very little rain in July (at least, after the often damp July 4 holiday!), August, and at least the first half of September. When I say "very little", I'm talking about maybe half an inch during that entire time period.

Let's continue on our very crude calculations. If you round it so we have 3 months with 0 rainfall, that means we have 9 months in which to fit our 36 inches of annual rainfall, or 9 months averaging 4 inches per month. We've just increased the month rainfall by one third. This is when things start to get tough to take. Our winter months actually tend more toward 5 or 6 inches of rain per month beginning in late November and running through February or March. We get about two thirds of our rain in one third of the year.

The other factor is that nearly all of this is rain, not snow. Rain absorbs light, snow reflects it. Four months of clouds and light-absorbing puddles can get to many of us.

On the bright side, the pussy willows are starting to come out, and many of the daffodils are above ground though perhaps not quite blooming yet.